Human fascination with life on Mars took a special step forward today, with the launch of a 520 day Mars simulation mission. A team of international researchers will try to experience what it would be like to travel to Mars, by locking themselves up in a windowless capsule for a year and a half. Three Russians, a Frenchman and a Chinese will endure the spartan conditions of a mock spaceship to study the effects of long isolation to help a real space crew cope better with stress and fatigue.